How do I know which AI engine and model wrote a chapter?

From version 1.9.6, every chapter in the book's workspace shows a small label with the engine and model that wrote its current text, for example "Gemini · gemini-2.5-pro" or "Ollama · qwen3:27b", with the time in the tooltip. When the engine differs from the one expected for the book (the book's chosen engine, or Gemini when no engine is chosen), the label is amber and the progress bar announces the fallback while the chapter is written. Chapters generated before 1.9.6 and imported chapters have no label. To keep the whole book on one engine, set "AI engine for this book" in Book details.